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Future batteries for Tesla: Power density and range

Future batteries for Tesla: Power density and range

Submitted by Timo on Wed, 2012-01-25 03:24

Everybody here, including me, has been relatively sure that batteries get smaller and smaller and at the same time cheaper and cheaper.

However there is a small problem with that. Automotive batteries do need to have relatively good power density as well as energy density. We see the result of that on Model S battery selections and corresponding performance. Bigger battery has more oomph than smaller one.

While I'm sure that in ten to fifteen years 1000 mile battery costs a bit less than 300 mile battery today and fits in the same space, it might well be that you actually need to buy that 1000 mile battery to get the same performance and not have third the size and price battery instead. Or swap to less energy density but greater power density batteries. What I have read it doesn't look that battery power densities increase at the same rate as energy densities (probably partially because it is less researched area of battery tech).

There are batteries with enormous power densities, but these tend to have poor energy density and vice versa. For example those li-air batteries that people so eagerly predict to be the ultimate automotive battery have poor power densities. With those it might turn out that you actually need to buy 2000 mile battery to get decent performance. This might not be desirable thing for price point of view.

I hope that nanotech gives us solutions to that problem as well, but at the mean time we might actually have to have huge range batteries. It might turn out to be necessity more than desire.

This means that in near future "small range batteries with fast charging times" might not be an option at all. This might also mean that in long run roadside charging is not required at all, you just want a charging possibility in end points of the journey. City centers, hotels etc. This also predicts death to all small range BEV:s like Leaf, i-MiEV etc. in very short time.

Volker.Berlin |
25 January 2012

This also predicts death to all small range BEVs like Leaf, i-MiEV etc. in very short time. (Timo)

I don't think so. As range increases at constant or decreasing cost, those "small range BEVs" will simply mutate into "long range BEVs".

Timo |
25 January 2012

By death I mean current generation of those. Their value drops fast so that no-one will buy them new or used. You are right that they just mutate to long range ones as a car model.

EdG |
25 January 2012

Perhaps a new term "hybrid" cars will mean one with 75% good energy density batteries and 25% good power density, the latter of which is charged by the former, allowing for quick acceleration when needed. This would be analogous to how a typical ICE-battery hybrid works today: use the electric to add power for acceleration.